A communications server, a method, a user device and a booking system

A method, performed in a communications server apparatus for a distributed sharding database related to a transportation service, the method comprising, under control of a processor of the server apparatus:

• determining whether rebalancing of a plurality of shard replicas stored on a plurality of server instances is required based on two or more quantitative metrics;
• if rebalancing is required, selecting a plurality of candidate rebalancing plans;
• ranking the candidates, and
• executing a selected rebalancing plan from the ranking if two or more quantitative metrics criteria are met for the selection.

A booking system for a transportation service, comprising:

• a communications server apparatus;
• at least one driver communications device;
• at least one user communications device;
• and
• a communications network equipment operable for the communications server apparatus, the at least one driver communications device, and the at least one user communications device, to establish communication with each other therethrough;
• wherein the at least one driver communications device comprises a first processor and a first memory, and the at least one user communications device comprises a second processor and a second memory;
• the at least one driver communications device being configured, under control of the first processor, to execute first instructions stored in the first memory to:
• send data regarding the driver location to a plurality of shard replicas stored on a plurality of server instances;
• the at least one user communications device being configured, under control of the second processor, to execute second instructions stored in the second memory to:
• request data from the plurality of shard replicas regarding an optimal driver for a proposed path of travel, based on a user location and destination;
• and
• the communications server apparatus comprises a third processor and a third memory, the communications server apparatus being configured, under control of the third processor, to execute third instructions stored in the third memory to:
• determine if rebalancing of the plurality of server instances is required based on a plurality of data requests by the at least one user communications device and two or more quantitative metrics, and
• rebalance the server instances based on selecting a plurality of candidate rebalancing plans, rank the candidates, and execute a selected rebalancing plan from the ranking if two or more quantitative metrics criteria are met for the selection.

A method, performed in a distributed sharding database related to a transportation service, the method comprising, under control of processors for a plurality of server instances storing a plurality of shard replicas:

• determining whether rebalancing is required based on CPU utilisation balance for the plurality of server instances;
• selecting candidate replacing plans based on each potential candidate satisfying a memory limitation test, and/or each potential candidate improving CPU utilisation balance;
• grouping the candidates according to the number of actions to implement each candidate;
• ranking each group of candidates based on a selection from the group consisting of:
• CPU utilisation balance, memory safety, level of redundancy across different availability zones, and any combination thereof,
• ordering winners from each group of candidates based on the number of actions to implement each candidate;
• and
• comparing the top ordered winner to each of the lower winners in order, based on a selection from the group consisting of:
• CPU utilisation balance, memory safety, level of redundancy across different availability zones, and any combination thereof.